Inductance coupling device



April 12, 1932. E. R WEIR ET AL 1,854Q008 INDUCTANCE COUPLING DEVICE Original Filed July 49, 1928 Fig. n.

Il n null mu inventors'.

rvhw R. Weir; L gcur" us W Richardson,

Patented Apr. 12, 1932 UNITEDy STATES PATENT OFFICE IRVIN R. WEIR, OF SCHENECTADY, AND LYCURG'US W. RICHARDSON, OF SCOTIA, NEW lYORK, ASSIGNORS- TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW 'YORK mDUCTANCE COUPLING DEVICE Original application med July 9, 1928, Serial No. 291,288. Divided and this'application med October 29,

i 1830. Serial No. 491,990.

Our present application is a division of our copending application, Serial No. 291,268, filed July 9, 1928, and entitled Signaling systems.

Our present invention relates to variable inductance coupling devices and more particularly to coupling devices of the auto transformer type.

It has for one of its objects to provide an improved inductance coupling dev ice for use between a plurality of circuits which are to be variably coupled together and by means r of which the degree of coupling between the circuits may be readily varied. n

A further object of the invention is to provide such a coupling device in which both sides of the different circuits which are intercoupled thereby are automatically maintained in balanced relation with respect to an intermediate point which may be ground, throughout all adjustments of coupling by the coupling device. o

Still a further ob'ect of our invention is to provide an inductance coil having a plurality of contacts in sliding engagement therewith and which may be rotated with respect to any of said contacts, and which further may be rotated with respect to certain of said contacts while it is maintained in fixed relation with respect to other of said contacts.

More particularly our invention has for one of its objects to provide an inductance coil for use in high power transmitters as 5 for coupling a high power amplifier of the push pull type to a suitable supply, o r load, circuit, as disclosed, for example, i'n our above mentioned parent applicatwn. lin that application we have shown our induc- 0 tance coil used to couple the input circuit of a pair of push pull connected electron discharge devices to a supply circuit, which may com rise a transmission line. The structure of t e coil is such that it has the advantage that both the grid connections and the supply line connections to the coil may be conveniently varied while the system is in operation by the simple rotation of a control member arranged outside of the housing of the amplifier. Further, either of the sets of connections may be varied independently of the other by a similar operation each set being maintained in symmetrical, or balanced, relation with respect to the cathode or ground connection.

The novel features which we believe to be characteristic of our invention are set forth with particularity in the appended claims. @ur invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings in which Fig. 1 represents an embodiment of our invention and Fig. 2 represents a detail thereof.

Referring to the drawings, we have shown therein a coil of cylindrical construction having oppositely wound sections 1 and 2 extending oppositely from a conducting slip ring 3 arranged at the center of the coil. Extending anially within the coil is a nonmetallic shaft t having slip rings 5 and 6 arranged at one end thereof, conducting supports 7 and 8 arranged thereon and within the coil sections 1 and 2 respectively, and a control handle 9 connected to the opposite end thereof, such that this shaft together with the supports 7 and 8 may be rotated as desired. rlhe supports 7 and 8 are of course insulated from the shaft d, and from each other. As shown in our parent application the control member 9 may be arranged outside of the housing of the transmitter in which the coil is used. A wall ot this housing is indicated at 20.

The supporting members 7 and 8 are connected to the slip rings 5 and 6 respectively through conductors 10 and 10a, carried in insulating tubes 34 and 35, these conductors being mounted for rotation with the shaft and extending through a suitable insulating bushing 11. rlihe bushing 11 comprises a part of the mechanism whereby the shaft- 4 is supported for rotation and has about it a pair of suitable concentric bearing members 12 and 13 which are adapted for rotation with respect to each other. The bearing member 13 is supported by an additional bearing l member 14 which, in turn, is attached to the supporting member 15, which may be attached in any suitable way to the housing. The shaft and the bearing members 12 and 13 are each rotatable with respect to the stationary bearing member 14 and the bearing members 12 and 13 are rotatable with respect to each other. The outer end of the section l of the coil is supported, by means of insulators 16, by the bearing member 13. The opposite end of the coil is supported by means of similar insulators 17 which are securely attached to a bearing member 18.- This bearing member is concentric with the shaft 4 and arranged within a concentric stationary bearing member 18a which is supported in any suitable way. The bearing 18 has a handle 19 attached thereto and arranged on the front of the panel 20. By means ot' this handle the bearing members 18 and 13 and the coil may be rotated about the shaft 4. This handle may be retained in a stationary position by means of a suitable locking device such as a member 2l which is mounted thereon and which is adapted frictionally to engage the panel 20.

Arranged for slidable engagement with each of the conducting supports 7 and 8 are contacts 22 and 23, these contacts being securely attached to the supports and adapted for rotation with the shaft 4. 'lhese contacts have a pair of prongs which project upon opposite sides and into engagement with one of the turns of the coil, such that as shaft 4 is revolved, the coil remaining stationary, each of the contacts 22 and 23 follows along the turn of the coil with which it is in engagement and is thereby caused to slide longitudinally of the supports 7 and 8. Suitable spring pressed brushes not shown serve to make good electrical connection between the coil and the contacts and similarbrushes indicated at 36 serve to make good electrical connection between the supports and the contacts. These contacts are spaced equally from the slip ring 3 and hence from the center of the coil, such that as the shaft 4 is revolved these contacts move in opposite directions, thereby producing equal changes in inductance between the center of the coil and the two contacts.

By m-eans of these contacts one of the circuits to be coupled together is connected to the coil. The conductors of this circuit are indicated at 32 and 33 connected to brushes engaging slip rings 5 and 6. This circuit may, for example, comprise the supply circuit of a push pull amplifier.

0n the outside of the coil and extending longitudinally of each section thereof are additional conducting supports 24 and 25. Mounted upon" these supports and in engagement with a turn of the coil are contacts 28 and 29, the structure of these contacts being identical with that of contacts 22 and 23.

lVhen the coil is revolved these contacts are caused to slide longitudinally of the supports 24 and 25 in opposite directions and thereby to produce equal changes in inductance between the' center of the coil and the two contacts.

By means of these contacts another of the circuits to be coupled together is connected to the coil. The conductors of this circuit are indicated at 26 and 27 connected to the supports 24 and 25. lVhen used for connection with an amplifier of the type indicated these conductors may extend to the grids of the discharge devices which may be suitably mounted on opposite sides of the coil.

Suitably mounted, as by means of a member 30 extending underneath the coil, and in engagement with the ring 3 is a brush 31 (Fig. 2). This brush may be connected to any point with respect to which the opposite sides of the circuits to be coupled are to be maintained in balanced relation. 'lhus this contact may be connected to ground, or in the application above indicated, to the cathodes ot the push pull amplifier.

As thus described it will be seen that electromotive force from the line comprising conductors 32 and 33 may be impressed upon the coil, symmetrically with respect to the center thereof, and that this electromotive force may be equally impressed upon the conductors 26 and 27.

For the purpose of varying the inductance of the line 32, 33 which includes the portion of the coil between the contacts 22 and 23, as for the purpose of tuning this circuit, which may be a transmission line, the handle 9 may be rotated, thereby causing the contacts 22 and 23 to move in opposite directions along the coil. The handle 9 may then be locked by means of the locking device 37 to the handle 19. By means of the handle 19, which may now be unlocked from the panel, the coil and the shaft 4 carrying the contacts 22 and 23 may be rotated together, causing the contacts 28 and 29 to move in opposite directions along the coil, thereby to vary in equal amounts the inductance between the center of the coil and the two conductors 26 and 27 Without effecting the position of contacts 22 and 23 upon the coil.

It will be apparent from the structure of the coil as thus described that the inductance between the contacts 28 and 29, and that between the transmission line contacts 22 and 23 may be continuously varied over a broad range and that either of them may be varied independently of the other. Further this coil comprises a compact unit which may be readily supported as a part of a transmitter equipment and conveniently controlled from the front of the transmitter panel. This coil possesses the further advantage that variations in the connections thereto do not maaataooe terially aiect'the distributed capacity existingvltween it and surrounding objects.

ile We have particularly mentioned the use of our inductance device as the input coil ot an amplifier, it will ci" course be understood that this is merely by way of reference to one of its important applications and that it has many other uses as well. lt may of course be used in any case where variable inductive coupling between two circuits is desired and particularly where the opposite sides of the two circuits are to be maintained in balanced relation with respect to an intermediate point or ground.

While We have shown a particular embodiment of our invention, it will of course be understood that we do not wish to be limited thereto since many modifications in the embodiment shown may be made. l/Ve contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, a rotatable inductance coil, a plurality of contacts arranged for sliding engagement along the turns of the coil, a supporting member for each of the contacts extending longitudinally of the coil, each contact being arranged for sliding engagement longitudinally of the supporting member as the coil is rotated and means for rotating the coil with respect to one of said contacts thereby to cause said contact to move longitudinally of the coil, and means whereby the position of certain of the other contacts upon the coil is maintained While said one contact is moved longitudinally of the coil.

2. In combination, a rotatable cylindrical inductance coil, a plurality of contacts arranged for sliding engagement along the turns of the coil, a supportinnr member for each of the contacts extending longitudinally of the coil, each contact being arranged for sliding engagement longitudinally of the supporting member as the coil is rotated and means for simultaneously rotating one of said contacts and the coil with respect to another contact thereby to cause said last named contact to move along the coil without aecting the1 position of said first contact upon the co1 3. In combination, a rotatable cylindrical inductance coil comprising oppositely wound sections extending from an intermediate point of the coil, a plurality of pairs of contacts, one contact of each pair being arranged for sliding engagement circumferentially of each section, a supporting member for the contacts extending longitudinally of the coil, each contact being arranged for sliding engagement longitudinally of the supporting member as the coil is rotated, means for rotating one pair of contacts with respect to the coil thereby to cause said contacts to move along the coil in opposite directions from said intermediate point of the coil, and means for revolving said contacts and coil with respect to another pair of contacts thereby to cause said other pair of contacts to move along the coil without affecting the position of said iirst contacts upon the coil.

l. ln combination, a rotatable cylindrical inductance coil, a plurality of pairs ot contacts arranged along said coil for sliding engagement with the turns of the coil and each of said contacts being supported to slide longitudinally of the coil as the coil is rotated, supporting means therefor extending longitudinally of the coil, each of said pairs of contacts being arranged upon opposite sides of an intermediate point of said coil whereby as the coil is rotated both contacts of each pair are equally displaced with respect to said intermediate point, a connection to said intermediate point and means whereby the position of each pair of contacts along the coil may be independently varied.

5. In combination, a rotatable cylindrical inductance coil, a rotatable shaft extending axially of said coil, a Contact mounted on said shaft and arranged to slide longitudinally of the shaft, said contact having engagement with a turn of said coil and arranged to slide longitudinally of said turn, whereby upon relative rotation of the shaft and coil said contact is moved along the coil, an additional Contact having engagement with a turn of said coil and arranged to slide longitudinally of the coil as the coil is rotated, and means to lock said shaft and coil together for simultaneous rotation with respect to said additional contact.

In witness whereof we have hereunto set our hands this 28th day of October, 1930.

IRVlN R. WEIR. LYCURGUS W. RICHARDSON. 

